As hunters, we commonly seek out information on the animals we hunt in hopes it will explain exactly when and where to find them. We quickly learn, time and again, it’s not that simple. All too often, we find that what works one time fails miserably the next, and we can go from a state of euphoria to desperation in the course of just a few hunts. Much of this inconsistency can be attributed to variability in animal behavior, weather, and habitat conditions. Over time, however, we gradually improve our hunting skills by combining our understanding of the animals with lessons learned from our many hunting experiences. Thus, it is beneficial to understand the ecology of the animals we pursue, as long as we keep our expectations in check and appreciate that the systems we hunt can be extremely variable. My objective here is to present a basic picture of elk ecology in Colorado. My hope is to give the novice elk hunter a better idea of where to begin and to help the seasoned hunter make a little more sense out of past experiences afield.What do elk eat?
Elk are herbivores capable of consuming diverse diets of grasses, forbs, and shrubs. The term forb refers to any broad-leaved herbaceous plant that is not a grass. Forbs are an important dietary component of elk and other wild ungulates and have high nutritional value during the growing season. Elk eat green grasses and forbs during the growing season but also commonly eat cured grasses and forbs during the winter. When elk and other ungulates eat shrubs, they typically select the tips of branches which comprise the current year’s growth and offer the most nutrients. It may be easiest to explain elk diets by contrasting them to those of some other common herbivores. Deer, for example, are often referred to as browsers because much of their diet is comprised of shrubs. Cattle and sheep, on the other hand, are commonly referred to as grazers because they consume large quantities of grass. The distinction between deer and livestock arises from physiological differences in the proportional sizes of their rumens (i.e., stomach) and in their associated digestive strategies. Elk are considered intermediate to deer and cattle/sheep, which means elk are better adapted to grass diets than deer yet are capable of consuming relatively large amounts of browse
. Therefore, elk should be capable of meeting their nutritional requirements across a greater spectrum of habitat conditions than deer or livestock as long as adequate forage quantities are available.
This basic knowledge of elk diets is useful for understanding why elk occur where they do. At a broad scale, elk can successfully occupy a diversity of habitats across Colorado because they are foraging generalists and are adaptable. You can find elk just about anywhere in Colorado west of Interstate 25. At a finer scale, we expect to find more elk where there is a greater abundance of grasses, forbs and shrubs, collectively referred to as “understory” in forested habitats. In sagebrush and mountain shrub habitats, understory typically refers to the abundance of grasses and forbs only. Using this information, you can begin to visualize more-productive and less-productive habitats based on the amount of vegetation covering the ground. For example, in conifer forests, elk seek out and feed in recently-burned areas, areas with beetle killed over-story, or small clear-cuts because these sites provide greater amounts of quality forage than the understory of a mature forest. When mature trees have been removed, grass, forb, and shrub species capitalize on the released nutrients and dominate the site until the forest regenerates. In such instances, elk utilize the mature forest primarily for cover and move into the openings to forage, typically during morning and evening. As a general rule, habitat types with greater understory will be preferred by elk.
Elk Habitat Use
Elk utilize most habitat types occurring in western Colorado at some point during the year. However, some habitat types are far more productive than others. Arguably, the most productive habitat for elk is aspen. Aspen typically has extremely productive understory and supports large numbers of elk. It is likely no coincidence that Colorado has both more aspen and more elk than any other western state or province.
Other extremely productive habitats that commonly occur in proximity to aspen are oakbrush and mountain shrub. Oakbrush habitat provides food and a good source of cover. It is not uncommon for elk to spend their days in oakbrush during hunting season because it provides great security. Oakbrush can be very difficult to hunt because it is thickly vegetated and difficult to quietly stalk through. Hunters that learn how to hunt oakbrush effectively, however, are often rewarded.
Perhaps the best combination of habitat for elk is mosaics of aspen, oakbrush, and mountain shrub, which provide optimal forage and cover. Aspen is also commonly located in proximity to conifer habitats. Spruce-fir forests with intermingled aspen stands are another example of prime elk habitat. The spruce-fir forest provides cover and the aspen understory provides a source of quality forage. Generally speaking, large tracts of mature conifer forest are not that productive for elk because they have limited understory. Ponderosa pine forests can be an exception because they often support a relatively robust, herbaceous understory, and, therefore, can be quite productive for elk, particularly along the front range of Colorado where there is less aspen and oakbrush.
As mentioned above, spruce-fir forests provide a good source of cover and are valuable when adjacent to more productive habitats. Lodgepole pine forests are typically unproductive and of utility to elk only when adjacent to other habitat or when used as escape cover from hunting pressure. As a general rule, the utility of conifer forests depends heavily on how much they are intermixed with meadows or other habitats. The exception to that rule is in October when forage in meadows and more open aspen stands has cured while forage in the conifer understory is still green and lush. Elk may not venture out in the open if the forage and security are better in coniferous forests.
Alpine habitats, above treeline, offer a productive habitat for elk during summer and early fall and can be heavily utilized by elk. Alpine habitat can offer good hunting opportunities during early-fall hunting seasons, particularly if adjacent conifer habitat is not very productive. Hunting pressure and frost both make the alpine less appealing as fall advances. At the other extreme, elk can be found in pinyon-juniper and lower-elevation sagebrush habitats, particularly later in the season as elk move to lower elevations.
Elk Migratory Behavior
Most elk utilize different areas during summer and winter and spend variable amounts of time transitioning between the two areas during the spring and fall. Thus, biologists refer to three major types of ungulate use areas: summer, transition, and winter range. Summer range typically includes the highest elevation elk habitats, transition range encompasses mid-elevation habitats, and winter range encompasses the lowest elevations. As with anything, there are exceptions to the rules. Elk habitat use and migratory behavior is heavily driven by weather. In mild years, some elk will remain at high elevations late into the fall and may spend winter at higher elevations on south-facing slopes that remain largely free of snow. In years with severe fall or winter weather, nearly all elk will migrate down to low elevations to seek forage and escape deep snow.
Migratory behavior is an important concept for hunters. Generally speaking, most elk will be at higher elevations (i.e., summer range) during archery and muzzleloader seasons and usually first rifle season in Colorado. In mild years, elk will remain at high elevations throughout the second rifle season and occasionally into the third season in many areas. This explains why CPW field personnel commonly refer to elk being located in dark timber during mild hunting seasons, and therefore, difficult to find. In contrast, when significant fall snowstorms occur, many elk will move to transition and winter ranges as early as second rifle season, which typically makes them more vulnerable.
Elk Response to Disturbance
It is well-documented that elk alter their movement patterns in response to human-related disturbance. For example, a number of studies have demonstrated that elk tend to avoid roads2, 3, 4, 5
and that their survival declines as density of roads increases because of increasing vulnerability2, 6, 7, 8
. During hunting season, elk will often seek out refuge on private lands or national parks where there is little or no hunting. In the White River National Forest in northwest Colorado, the opening day of archery season caused elk to move from public to private land9,10
. Similarly, in the San Luis Valley in south-central Colorado, elk moved into Great Sand Dunes National Park in response to the opening of archery season11
. Opening of rifle seasons are thought to cause additional shifts by elk away from public land to secure areas. Generally speaking, elk are adept at seeking out refuges to escape hunting pressure and will move many miles to do so.
The above information explains why hunters with access to private lands that are managed for limited hunting typically do well. Likewise, hunters gaining access to limited-harvest units by using preference points also fare well. However, most hunters do not have access to these optimal hunting situations during most years. For public-land hunters in over-the-counter units, efforts to get away from roads generally pay off. There tend to be fewer hunters and more elk in more remote areas. It is also helpful to obtain maps showing secondary roads, terrain features and public/private land ownership to evaluate where elk may be more likely to move in response to disturbance. If you lack the ability to hunt in remote areas, getting off the road even a short distance and still-hunting on foot can greatly increase your opportunities. It is not uncommon for animals to bed down in thick cover near roads and not be disturbed, even as hunters pass by on the road throughout the day. When hunting roaded areas, it is often helpful to identify patches of heavy cover where it appears elk might bed down to avoid being disturbed.
Putting It All Together
Many hunters know the general location they intend to hunt based on past experience, contacts, recommendations, etc. However, if you’re new to Colorado elk hunting, there are a few things worth considering:
- Colorado’s largest elk herds occur west of the Continental Divide.
- Colorado’s highest elk densities generally occur in association with aspen, oakbrush, and mountain shrub habitats.
- Public-land hunting opportunities span everything from remote wilderness areas to heavily-roaded forests and rangelands.
Once you’ve determined the general location you plan to hunt, the next consideration is when you plan to hunt. If you plan to hunt early in the season (e.g., late August through mid-October), a majority of elk are likely to be at higher elevations. If you plan to hunt later (e.g., late October through December), elk are likely to be mid-slope or even down on winter range just above the valley floors or plains. Many rifle hunters head to the field in late October and early November. At this time of year, maintaining flexibility with your hunting plans can be an effective strategy. Elk can be anywhere on the mountain depending on weather events, and it is best not to lock yourself in to exclusively hunting one spot. Elk are large, herd animals that leave abundant sign. If you’re not seeing evidence in your primary area, it’s advisable to seek out other areas.
After deciding when to hunt and factoring in weather, the next step is to evaluate habitat in terms of forage, security cover, and roads. As a recap, elk prefer habitats with abundant understory, which typically include aspen, oakbrush, and mountain shrub habitats. These habitat types are often intermixed with, or adjacent to, conifer forest. Areas with mosaics of aspen, shrub, and conifer are preferable to large, unbroken expanses of spruce-fir habitat, for example. During hunting season, in particular, elk will tend to avoid roads and place a heavier emphasis on seeking out security cover or refuge areas. It is useful to consider the spatial arrangement of public and private land parcels on the landscape you intend to hunt. If public-private parcels are intermixed, hunting public land near private land may be advantageous as animals will likely move between private and public land in that scenario. On the other hand, hunting public land adjacent to large blocks of private land with minimal hunting pressure will be less ideal. In Colorado, it is the hunter’s responsibility to know land ownership boundaries and not trespass, even where private land is not fenced or signed.
Ultimately, these various considerations should help you assess the overall landscape you intend to hunt: Is there ample forage and security cover? Are you far enough away from potential refuge areas (e.g., large blocks of private land, National Parks) such that elk will likely remain on public land even when pressured by hunters? If so, where are elk likely to go when pressured? What are the relative road densities across the landscape? Are there “holes” that you can access? When you factor in all these considerations, it should be possible to assess a large landscape and identify specific spots to hunt. In summary, areas to select are those that provide abundant forage, ample security cover, fewer roads, and do not have obvious refuges.
- Hofmann, R. R. 1989. Evolutionary steps of ecophysiological adaptation and diversification of ruminants: a comparative view of their digestive system. Oecologia 78:443-457.
- Cole, E. K., M. D. Pope, and R. G. Anthony. 1997. Effects of road management on movement and survival of Roosevelt elk. Journal of Wildlife Management 61:1115–1126.
- Lyon, L. 1979. Habitat effectiveness for elk as influenced by roads and cover. Journal of Forestry 77:658–660.
- Rost, G. R., and J. A. Bailey. 1979. Distribution of mule deer and elk in relation to roads. Journal of Wildlife Management 43:634–641.
- Rowland, M. M., M. J. Wisdom, B. K. Johnson, and J. G. Kie. 2000. Elk distribution and modeling in relation to roads. Journal of Wildlife Management 64:672–684.
- Hayes, S. G., D. J. Leptich, and P. Zager. 2002. Proximate factors affecting male elk hunting mortality in northern Idaho. Journal of Wildlife Management 66:491–499.
- McCorquodale, S. M., R. Wiseman, and C. Les Marcum. 2003. Survival and harvest vulnerability of elk in the Cascade Range of Washington. Journal of Wildlife Management 67:248–257.
- Unsworth, J. W., L. Kuck, M. D. Scott, and E. O. Garton. 1993. Elk mortality in the Clearwater Drainage of northcentral Idaho. Journal of Wildlife Management 57:495–502.
- Conner, M. M., G. C. White, and D. J. Freddy. 2001. Elk movements in response to early-season hunting in northwest Colorado. Journal of Wildlife Management 65:926–940.
- Vieira, M. E. P., M. M. Conner, G. C. White, and D. J. Freddy. 2003. Effects of archery hunter numbers and opening dates on elk movement. Journal of Wildlife Management 67:717–728.
- Davidson, G. A. 2007. Analyzing elk movements and distributions in Colorado using generalized linear models. Thesis, Colorado State University, Fort Collins, USA.